PROJECT SUMMARY Stroke is a leading cause of serious long-term disability within the United States, and it affects an estimated 6.6 million Americans over age 20. Medical advances in treatment of acute stroke and an aging population have resulted in a greater number of stroke survivors in our population, and many stroke survivors return directly home. With a greater number of stroke survivors living in their local community, it is critical to determine which features of the local environment best support stroke survivors' functional status, especially features that support mobility. Mobility impacts health through various mechanisms, including social engagement, community involvement, and access to health care resources. Using a mixed methods study design, the proposed project will determine which features of the outdoor environment are most important for mobility and functional status in the first 18 months post-stroke. This research project will consist of a secondary data analysis of existing data by combining three, rich data sources and primary data collection using mobile inertial measurement units and qualitative methods. Specifically, this research project will address the following aims: 1) Examine the moderating effect of environmental features found on participants' residential blocks on the relationship between stroke severity and 18-month trajectory of functional status post stroke, 2) Identify environmental features that moderate the relationship between stroke severity and mobility adaption (i.e. slower gait speed) in real-time using wearable sensors (i.e. mobile inertial measurement units), and 3) Identify the most salient environmental features for functional status and mobility as reported by stroke survivors using qualitative interviews. The mixed methods approach allows the examination of which environmental features interact with stroke impairment to result in differential functional status (Aim 1), how stroke impairment interacts with environmental features to affect mobility (Aim 2), and why environmental features affect mobility and functional status from the perspective of stroke survivors themselves (Aim 3). This research will identify potential ways to increase stroke survivors' mobility and independence by determining how to maximize the accessibility of the outdoor built environment. The findings of this research will inform planning and policy regarding which components of the built environment are most important for survivors' mobility and functional independence. Ultimately, positive environmental changes can improve stroke survivors' functional independence and decrease stroke survivors' reliance on caregivers, premature relocation to nursing home facilities, and development of secondary conditions (e.g. depression, cognitive decline).